Mobil 1 full synthetic or Pennzoil Ultra in 10W-30. More cleaners = happier engine

 

I've got Valvoline Max life 20-50 in mine

 

what ever oil you use you should stick with it. Dont go using a differnt brand oil and weight every time you change your oil.

 

I've been using valvoline max life 10-30. I don't see the problem in switching oils, really. I've used dino, syn blend, and full syn with no problems. All have been 10-30 though. Stick with reputable brands, though, I wouldn't go generic at all.

 

Btw, wal-mart has 5 quart jugs of pennz ultra and mobil 1 for $25-$27. Pick up oil filter of choice at wherever, I go wix ($6). Great prices.

 

thats what my old man says

 

I just used rotela T 10w-30 and some zddp additive in mine and it seems to run better than ever.

Be aware that in newer motors the zddp stuff can harm your catalytic converter, so use at your own risk!

My exhaust will need replacing soon anyway, so I thought it was worth the risk.

If you can't be good, be good at it!

 

I'm a service tech at a dealership and do tons of oil changes on cars. The best oil you can use in an 4.0L XJ would be 10w30, it's in the owner's manual.

As for what brand/type you should use, I'd recommend Valvoline Syntec (I've been using it for a long time), Valvoline High Mileage (it just has more detergents than syntec), or Mobil 1 synthetic. Pennzoil and Quaker State suck, they're cheap and are of low quality. Avoid them.

Synthetic oil is worth the extra expense. Conventional is only recommended to have 3 month/3,000 mile change intervals. Synthetic has a recommended 6 month/6,000 mile change interval.

Basically, with synthetic you can go farther on one oil change than you would with dino.

 

most modern cars recommend 5 months and 5000 miles on any oil. hell toyota wouldn't change the oil in my folks camary until the light came on and that took 7 months. whats sad is the oil that came out was better looking than my jeep after 2 months :/

 

Pennzoil cheap and low quality? Does that explain my buddy's chevy engines that all have well over 300k on the clock? One has 560k, and he always uses Pennzoil conventional. Where's the documentation on the low quality?

 

ill bite. 5w30 in the winter (still havent decided and a brand yet). Spring/Summer/Fall i run 10w30, John Deere break in oil. John Deere Filters.

 

Everyone I've known who used Quaker State or Pennzoil have had their engines fail on them at early mileage (meaning between 90k and 110k). Your buddy must have a 350s or 305s, they're great engines. He's pretty lucky too lol.

Personally I'd never run the stuff, but it's personal preference I suppose.

 

Just got my Jeep but the PO ran 20w50 in the summer and 10-30 in the winter. I just possibly found a knock at 166k miles. I've always ran the suggested synthetic weight in all my vehicles. The 20w50 just seems too heavy to me. Just my opinion .

 

What about Pennzoil Ultra? I've never heard anything bad about it, and I don't see why Pennzoil would produce and market something that would make an engine fail in early mileage... How was the maintenance on those engines you saw, besides just oil change? I don't want to sound abrasive or rude, I've just never heard someone hash on the old Pennz.

 

I heard the Wix will raise your oil pressure a bit because of the way it's built. What does your run?